1
|
Erol ÖD, Şenocak Ş, Aerts-Kaya F. The Role of Rab GTPases in the development of genetic and malignant diseases. Mol Cell Biochem 2024; 479:255-281. [PMID: 37060515 DOI: 10.1007/s11010-023-04727-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.
Collapse
Affiliation(s)
- Özgür Doğuş Erol
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Şimal Şenocak
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Fatima Aerts-Kaya
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey.
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey.
| |
Collapse
|
2
|
G. Dornan L, C. Simpson J. Rab6-mediated retrograde trafficking from the Golgi: the trouble with tubules. Small GTPases 2023; 14:26-44. [PMID: 37488775 PMCID: PMC10392741 DOI: 10.1080/21541248.2023.2238330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 07/26/2023] Open
Abstract
Next year marks one-quarter of a century since the discovery of the so-called COPI-independent pathway, which operates between the Golgi apparatus and the endoplasmic reticulum (ER) in eukaryotic cells. Unlike almost all other intracellular trafficking pathways, this pathway is not regulated by the physical accumulation of multisubunit proteinaceous coat molecules, but instead by the small GTPase Rab6. What also sets it apart from other pathways is that the transport carriers themselves often take the form of tubules, rather than conventional vesicles. In this review, we assess the relevant literature that has accumulated to date, in an attempt to provide a concerted description of how this pathway is regulated. We discuss the possible cargo molecules that are carried in this pathway, and the likely mechanism of Rab6 tubule biogenesis, including how the cargo itself may play a critical role. We also provide perspective surrounding the various molecular motors of the kinesin, myosin and dynein families that have been implicated in driving Rab6-coated tubular membranes long distances through the cell prior to delivering their cargo to the ER. Finally, we also raise several important questions that require resolution, if we are to ultimately provide a comprehensive molecular description of how the COPI-independent pathway is controlled.
Collapse
Affiliation(s)
- Lucy G. Dornan
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| | - Jeremy C. Simpson
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| |
Collapse
|
3
|
Nozawa T, Toh H, Iibushi J, Kogai K, Minowa-Nozawa A, Satoh J, Ito S, Murase K, Nakagawa I. Rab41-mediated ESCRT machinery repairs membrane rupture by a bacterial toxin in xenophagy. Nat Commun 2023; 14:6230. [PMID: 37802980 PMCID: PMC10558455 DOI: 10.1038/s41467-023-42039-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 09/26/2023] [Indexed: 10/08/2023] Open
Abstract
Xenophagy, a type of selective autophagy, is a bactericidal membrane trafficking that targets cytosolic bacterial pathogens, but the membrane homeostatic system to cope with bacterial infection in xenophagy is not known. Here, we show that the endosomal sorting complexes required for transport (ESCRT) machinery is needed to maintain homeostasis of xenophagolysosomes damaged by a bacterial toxin, which is regulated through the TOM1L2-Rab41 pathway that recruits AAA-ATPase VPS4. We screened Rab GTPases and identified Rab41 as critical for maintaining the acidification of xenophagolysosomes. Confocal microscopy revealed that ESCRT components were recruited to the entire xenophagolysosome, and this recruitment was inhibited by intrabody expression against bacterial cytolysin, indicating that ESCRT targets xenophagolysosomes in response to a bacterial toxin. Rab41 translocates to damaged autophagic membranes via adaptor protein TOM1L2 and recruits VPS4 to complete ESCRT-mediated membrane repair in a unique GTPase-independent manner. Finally, we demonstrate that the TOM1L2-Rab41 pathway-mediated ESCRT is critical for the efficient clearance of bacteria through xenophagy.
Collapse
Affiliation(s)
- Takashi Nozawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Hirotaka Toh
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Junpei Iibushi
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kohei Kogai
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Atsuko Minowa-Nozawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Junko Satoh
- Medical Research Support Center, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Shinji Ito
- Medical Research Support Center, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kazunori Murase
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Ichiro Nakagawa
- Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
| |
Collapse
|
4
|
The role of CaMKK2 in Golgi-associated vesicle trafficking. Biochem Soc Trans 2023; 51:331-342. [PMID: 36815702 PMCID: PMC9987998 DOI: 10.1042/bst20220833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is a serine/threonine-protein kinase, that is involved in maintaining various physiological and cellular processes within the cell that regulate energy homeostasis and cell growth. CaMKK2 regulates glucose metabolism by the activation of downstream kinases, AMP-activated protein kinase (AMPK) and other calcium/calmodulin-dependent protein kinases. Consequently, its deregulation has a role in multiple human metabolic diseases including obesity and cancer. Despite the importance of CaMKK2, its signalling pathways and pathological mechanisms are not completely understood. Recent work has been aimed at broadening our understanding of the biological functions of CaMKK2. These studies have uncovered new interaction partners that have led to the description of new functions that include lipogenesis and Golgi vesicle trafficking. Here, we review recent insights into the role of CaMKK2 in membrane trafficking mechanisms and discuss the functional implications in a cellular context and for disease.
Collapse
|
5
|
Liu S, Pokrovskaya ID, Storrie B. High-Pressure Freezing Followed by Freeze Substitution: An Optimal Electron Microscope Technique to Study Golgi Apparatus Organization and Membrane Trafficking. Methods Mol Biol 2023; 2557:211-223. [PMID: 36512217 DOI: 10.1007/978-1-0716-2639-9_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A major goal of structural biologists is to preserve samples as close to their living state as possible. High-pressure freezing (HPF) is a state-of-art technique that freezes the samples at high pressure (~2100 bar) and low temperature (-196 °C) within milliseconds. This ultrarapid fixation enables simultaneous immobilization of all cellular components and preserves the samples in a near-native state. This facilitates the study of dynamic processes in Golgi apparatus organization and membrane trafficking. The work in our laboratory shows that high-pressure freezing followed by freeze substitution (FS), the introduction of organic solvents at low temperature prior to plastic embedding, can better preserve the structure of Golgi apparatus and Golgi-associated vesicles. Here, we present a protocol for freezing monolayer cell cultures on sapphire disks followed by freeze substitution. We were able to use this protocol to successfully study Golgi organization and membrane trafficking in HeLa cells. The protocol gives decidedly better preservation of Golgi apparatus and associated vesicles than conventional chemically fixed preparation and as a plastic embedded preparation can be readily extended to 3D electron microscopy imaging through sequential block face-scanning electron microscopy. The 3D imaging of a multi-micron thick organelle such as the Golgi apparatus located near the cell nucleus is greatly facilitated relative to hydrated sample imaging techniques such as cryo-electron microscopy.
Collapse
Affiliation(s)
- Shijie Liu
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Irina D Pokrovskaya
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Brian Storrie
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| |
Collapse
|
6
|
Domínguez Cadena LC, Schultz TE, Zamoshnikova A, Donovan ML, Mathmann CD, Yu CH, Mori G, Stow JL, Blumenthal A. Rab6b localizes to the Golgi complex in murine macrophages and promotes tumor necrosis factor release in response to mycobacterial infection. Immunol Cell Biol 2021; 99:1067-1076. [PMID: 34555867 DOI: 10.1111/imcb.12503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/27/2021] [Accepted: 09/21/2021] [Indexed: 11/30/2022]
Abstract
The proinflammatory cytokine tumor necrosis factor (TNF) plays a central role in the host control of mycobacterial infections. Expression and release of TNF are tightly regulated, yet the molecular mechanisms that control the release of TNF by mycobacteria-infected host cells, in particular macrophages, are incompletely understood. Rab GTPases direct the transport of intracellular membrane-enclosed vesicles and are important regulators of macrophage cytokine secretion. Rab6b is known to be predominantly expressed in the brain where it functions in retrograde transport and anterograde vesicle transport for exocytosis. Whether it executes similar functions in the context of immune responses is unknown. Here we show that Rab6b is expressed by primary mouse macrophages, where it localized to the Golgi complex. Infection with Mycobacterium bovis bacille Calmette-Guérin (BCG) resulted in dynamic changes in Rab6b expression in primary mouse macrophages in vitro as well as in organs from infected mice in vivo. We further show that Rab6b facilitated TNF release by M. bovis BCG-infected macrophages, in the absence of discernible impact on Tnf messenger RNA and intracellular TNF protein expression. Our observations identify Rab6b as a positive regulator of M. bovis BCG-induced TNF trafficking and secretion by macrophages and positions Rab6b among the molecular machinery that orchestrates inflammatory cytokine responses by macrophages.
Collapse
Affiliation(s)
- Leslie C Domínguez Cadena
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Thomas E Schultz
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Alina Zamoshnikova
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Meg L Donovan
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Carmen D Mathmann
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Chien-Hsiung Yu
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Giorgia Mori
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Antje Blumenthal
- The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, QLD, Australia
| |
Collapse
|
7
|
Lei Z, Wang J, Zhang L, Liu CH. Ubiquitination-Dependent Regulation of Small GTPases in Membrane Trafficking: From Cell Biology to Human Diseases. Front Cell Dev Biol 2021; 9:688352. [PMID: 34277632 PMCID: PMC8281112 DOI: 10.3389/fcell.2021.688352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/09/2021] [Indexed: 01/04/2023] Open
Abstract
Membrane trafficking is critical for cellular homeostasis, which is mainly carried out by small GTPases, a class of proteins functioning in vesicle budding, transport, tethering and fusion processes. The accurate and organized membrane trafficking relies on the proper regulation of small GTPases, which involves the conversion between GTP- and GDP-bound small GTPases mediated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Emerging evidence indicates that post-translational modifications (PTMs) of small GTPases, especially ubiquitination, play an important role in the spatio-temporal regulation of small GTPases, and the dysregulation of small GTPase ubiquitination can result in multiple human diseases. In this review, we introduce small GTPases-mediated membrane trafficking pathways and the biological processes of ubiquitination-dependent regulation of small GTPases, including the regulation of small GTPase stability, activity and localization. We then discuss the dysregulation of small GTPase ubiquitination and the associated human membrane trafficking-related diseases, focusing on the neurological diseases and infections. An in-depth understanding of the molecular mechanisms by which ubiquitination regulates small GTPases can provide novel insights into the membrane trafficking process, which knowledge is valuable for the development of more effective and specific therapeutics for membrane trafficking-related human diseases.
Collapse
Affiliation(s)
- Zehui Lei
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
8
|
Deng S, Liu J, Wu X, Lu W. Golgi Apparatus: A Potential Therapeutic Target for Autophagy-Associated Neurological Diseases. Front Cell Dev Biol 2020; 8:564975. [PMID: 33015059 PMCID: PMC7509445 DOI: 10.3389/fcell.2020.564975] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022] Open
Abstract
Autophagy has dual effects in human diseases: appropriate autophagy may protect cells from stress, while excessive autophagy may cause cell death. Additionally, close interactions exist between autophagy and the Golgi. This review outlines recent advances regarding the role of the Golgi apparatus in autophagy. The signaling processes of autophagy are dependent on the normal function of the Golgi. Specifically, (i) autophagy-related protein 9 is mainly located in the Golgi and forms new autophagosomes in response to stressors; (ii) Golgi fragmentation is induced by Golgi-related proteins and accompanied with autophagy induction; and (iii) the endoplasmic reticulum-Golgi intermediate compartment and the reticular trans-Golgi network play essential roles in autophagosome formation to provide a template for lipidation of microtubule-associated protein 1A/1B-light chain 3 and induce further ubiquitination. Golgi-related proteins regulate formation of autophagosomes, and disrupted formation of autophagy can influence Golgi function. Notably, aberrant autophagy has been demonstrated to be implicated in neurological diseases. Thus, targeted therapies aimed at protecting the Golgi or regulating Golgi proteins might prevent or ameliorate autophagy-related neurological diseases. Further studies are needed to investigate the potential application of Golgi therapy in autophagy-based neurological diseases.
Collapse
Affiliation(s)
- Shuwen Deng
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jia Liu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xiaomei Wu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Wei Lu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
9
|
Abstract
The Golgi apparatus is a central intracellular membrane-bound organelle with key functions in trafficking, processing, and sorting of newly synthesized membrane and secretory proteins and lipids. To best perform these functions, Golgi membranes form a unique stacked structure. The Golgi structure is dynamic but tightly regulated; it undergoes rapid disassembly and reassembly during the cell cycle of mammalian cells and is disrupted under certain stress and pathological conditions. In the past decade, significant amount of effort has been made to reveal the molecular mechanisms that regulate the Golgi membrane architecture and function. Here we review the major discoveries in the mechanisms of Golgi structure formation, regulation, and alteration in relation to its functions in physiological and pathological conditions to further our understanding of Golgi structure and function in health and diseases.
Collapse
Affiliation(s)
- Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Erpan Ahat
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
| |
Collapse
|
10
|
Abstract
The Golgi apparatus is a central sorting station in the cell. It receives newly synthesized molecules from the endoplasmic reticulum and directs them to different subcellular destinations, such as the plasma membrane or the endocytic pathway. Importantly, in the last few years, it has emerged that the maintenance of Golgi structure is connected to the proper regulation of membrane trafficking. Rab proteins are small GTPases that are considered to be the master regulators of the intracellular membrane trafficking. Several of the over 60 human Rabs are involved in the regulation of transport pathways at the Golgi as well as in the maintenance of its architecture. This chapter will summarize the different roles of Rab GTPases at the Golgi, both as regulators of membrane transport, scaffold, and tethering proteins and in preserving the structure and function of this organelle.
Collapse
|
11
|
Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2018. [PMID: 29239692 DOI: 10.1080/215412481397833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
Collapse
Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| |
Collapse
|
12
|
Abstract
GTP-ases of the Rab family (about 70 in human) are key regulators of intracellular transport and membrane trafficking in eukaryotic cells. Remarkably, almost one third associate with membranes of the Golgi complex and TGN (trans-Golgi network). Through interactions with a variety of effectors that include molecular motors, tethering complexes, scaffolding proteins and lipid kinases, they play an important role in maintaining Golgi architecture.
Collapse
Affiliation(s)
- Bruno Goud
- a Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport , Paris , France
| | - Shijie Liu
- b Department of Physiology and Biophysics , University of Arkansas for Medical Sciences , Little Rock , USA
| | - Brian Storrie
- b Department of Physiology and Biophysics , University of Arkansas for Medical Sciences , Little Rock , USA
| |
Collapse
|
13
|
Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2017; 9:158-181. [PMID: 29239692 DOI: 10.1080/21541248.2017.1397833] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
Collapse
Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| |
Collapse
|
14
|
Golgi trafficking defects in postnatal microcephaly: The evidence for “Golgipathies”. Prog Neurobiol 2017; 153:46-63. [DOI: 10.1016/j.pneurobio.2017.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 12/17/2022]
|
15
|
Cox JV, Kansal R, Whitt MA. Rab43 regulates the sorting of a subset of membrane protein cargo through the medial Golgi. Mol Biol Cell 2016; 27:1834-44. [PMID: 27053659 PMCID: PMC4884073 DOI: 10.1091/mbc.e15-03-0123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/31/2016] [Indexed: 11/11/2022] Open
Abstract
To evaluate the role of cytoplasmic domains of membrane-spanning proteins in directing trafficking through the secretory pathway, we generated fluorescently tagged VSV G tsO45 with either the native G tail (G) or a cytoplasmic tail derived from the chicken AE1-4 anion exchanger (G(AE)). We previously showed that these two proteins progressed through the Golgi with distinct kinetics. To investigate the basis for the differential sorting of G and G(AE), we analyzed the role of several Golgi-associated small GTP-binding proteins and found that Rab43 differentially regulated their transport through the Golgi. We show that the expression of GFP-Rab43 arrested the anterograde transport of G(AE) in a Rab43-positive medial Golgi compartment. GFP-Rab43 expression also inhibited the acquisition of endoH-resistant sugars and the surface delivery of G(AE), as well as the surface delivery of the AE1-4 anion exchanger. In contrast, GFP-Rab43 expression did not affect the glycosylation or surface delivery of G. Unexpectedly, down-regulation of endogenous Rab43 using small interfering RNA resulted in an increase in the accumulation of G(AE) on the cell surface while having minimal effect on the surface levels of G. Our data demonstrate that Rab43 regulates the sorting of a subset of membrane-spanning cargo as they progress through the medial Golgi.
Collapse
Affiliation(s)
- John V Cox
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163
| | - Rita Kansal
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163
| | - Michael A Whitt
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163
| |
Collapse
|
16
|
Liu S, Majeed W, Kudlyk T, Lupashin V, Storrie B. Identification of Rab41/6d Effectors Provides an Explanation for the Differential Effects of Rab41/6d and Rab6a/a' on Golgi Organization. Front Cell Dev Biol 2016; 4:13. [PMID: 26973836 PMCID: PMC4771738 DOI: 10.3389/fcell.2016.00013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 02/09/2016] [Indexed: 11/24/2022] Open
Abstract
Unexpectedly, members of the Rab VI subfamily exhibit considerable variation in their effects on Golgi organization and trafficking. By fluorescence microscopy, neither depletion nor overexpression of the GDP-locked form of Rab6a/a', the first trans Golgi-associated Rab protein discovered, affects Golgi ribbon organization while, on the other hand, both Rab41/6d depletion and overexpression of GDP-locked form cause Golgi fragmentation into a cluster of punctate elements, suggesting that Rab41/6d has an active role in maintenance of Golgi ribbon organization. To establish a molecular basis for these differences, we screened for Rab41/6d interacting proteins by yeast two-hybrid assay. 155 non-repetitive hits were isolated and sequenced, and after searching in NCBI database, 102 different proteins and protein fragments were identified. None of these hits overlapped with any published Rab6a/a' effector. Eight putative Rab41 interactors involved in membrane trafficking were found. Significantly, these exhibited a preferential interaction with GTP- vs. GDP-locked Rab41/6d. Of the 8 hits, the dynactin 6, syntaxin 8, and Kif18A plasmids were the only ones expressing the full-length protein. Hence, these 3 proteins were selected for further study. We found that depletion of dynactin 6 or syntaxin 8, but not Kif18A, resulted in a fragmented Golgi apparatus that displayed a Rab41/6d knockdown phenotype, i.e., the Golgi apparatus was disrupted into a cluster of punctate Golgi elements. Co-immunoprecipation experiments verified that the interaction of dynactin 6 and syntaxin 8 with GTP-locked Rab41/6d was stronger than that with wild type Rab41/6d and least with the GDP-locked form. In contrast, co-immunoprecipitation interaction with Rab6a was greatest with the GDP-locked Rab6a, suggestive of a non-physiological interaction. In conclusion, we suggest that dynactin 6, a subunit of dynactin complex, the minus-end-directed, dynein motor, provides a sufficient molecular basis to explain the active role of Rab41/6d in maintaining Golgi ribbon organization while syntaxin 8 contributes more indirectly to Golgi positioning.
Collapse
Affiliation(s)
- Shijie Liu
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| | - Waqar Majeed
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| | - Tetyana Kudlyk
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| | - Vladimir Lupashin
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| | - Brian Storrie
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| |
Collapse
|
17
|
Liu S, Storrie B. How Rab proteins determine Golgi structure. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:1-22. [PMID: 25708460 DOI: 10.1016/bs.ircmb.2014.12.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rab proteins, small GTPases, are key regulators of mammalian Golgi apparatus organization. Based on the effect of Rab activation state, Rab proteins fall into two functional classes. In Class1, inactivation induces Golgi ribbon fragmentation and/or redistribution of Golgi enzymes to the Endoplasmic Reticulum, while overexpression of wild type or activation has little, if any, effect on Golgi ribbon organization. In Class 2, the reverse is true. We give emphasis to Rab6, the most abundant Golgi-associated Rab protein. Rab6 depletion in HeLa cells causes an increase in Golgi cisternal number, longer, more continuous cisternae, and a pronounced accumulation of vesicles; the effect of Rab6 on Golgi ribbon organization is probably through regulation of vesicle transport. In effector studies, motor proteins and their regulators are found to be key Rab6 effectors. A related Rab, Rab41, affects Golgi ribbon organization in a contrasting manner. The balance between minus- and plus-end directed motor recruitment may well be the major Rab-dependent factor in Golgi ribbon organization.
Collapse
Affiliation(s)
- Shijie Liu
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Brian Storrie
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| |
Collapse
|